The article ?Adolescents Living the 24/7 Lifestyle: Effects of Caffeine and Technology on Sleep Duration and Daytime Functioning? (Pediatrics [2009]: e1005-e1010) describes a study in which researchers investigated whether there is a relationship between the amount of sleep and caffeine consumption. They found that teenagers who usually get less than 8 hours of sleep on school nights were more likely to report falling asleep during school and to consume more caffeine on average than teenagers who usually get 8 to 10 hours of sleep on school nights.?

a. Is the study described an observational study or an experiment??

b. Is it reasonable to conclude that getting less than 8 hours of sleep on school nights causes teenagers to fall asleep during school and to consume more caffeine, on average? Explain.?

Table 2.1.